【摘要】 目的:探讨Aβ25-35诱导体外去血清培养的PC12细胞周期变化及对P53和Cyclin D1基因表达的影响。方法:PC12细胞同步于G0期,采用终浓度为0-45μmol/L或浓度为25μmol/L Aβ25-35处理PC12细胞,用MTT比色法分析细胞存活率;流式细胞仪检测分析细胞周期的改变;RT-PCR和Western blot从mRNA及蛋白水平检测P53和Cyclin D1基因的变化。结果:随着Aβ25-35剂量的增加,PC12细胞存活率降低(P<0.01);流式细胞仪分析表明去血清培养24 h可使约90%PC12细胞停滞于G0/G1期,25μmol/L Aβ25-35诱导组8,16,24 h与对照组比较,S期百分率明显增加(P<0.01),16 h后细胞凋亡率明显增加(P<0.01),可见明显的亚二倍体峰(Ap峰);P53 mR-NA表达和P53蛋白表达降低、Cyclin D1 mRNA表达和Cyclin D1蛋白表达增高。结论:Aβ25-35降低去血清培养的PC12细胞存活率,诱导同步化于G0/G1的PC12细胞重新进入细胞周期,并阻滞于S期,同时出现凋亡,可能与下调P53的表达,上调Cyclin D1的表达有关。更多还原

【Abstract】 Objective: To study the effect on cell cycle and the expression of P53, Cyclin D1 of serum-deprived PC12 cells induced by Aβ_25-35.Methods: PC12 cells were synchronized by 24 hours serum deprivation and were treated with different concentration of Aβ_25-35（0-45 μmol/L） for different time.The cell survival rate was evaluated by MTT assay.Cell cycle distribution was analyzed by flow cytometry（FCM）.Protein and mRNA expression of P53 and Cyclin D1 were detected by RT-PCR and Western-blot respectively.Results: Aβ_25-35 decreased the survival rate of PC12 cells in a dose-dependent manner.About 90% PC12 cells were found arrest on G₀/G₁ by FCM after deprived of serum for 24 hours.Treated with 25 μmol/L Aβ_25-35 for 8,16 and 24 hours,the percent of S phase cells was raised remarkably（P<0.01） at 8 h,and the percent of S phase cells was declined gradually after 16 hours.Meanwhile the apoptotic rate was detected being increased obviously between 16 h and 24 h（P<0.01） and the obvious hypodiploid peak ahead of G₀/G₁ phase（Ap） was shown.Aβ_25-35decreased the expression of P53 mRNA and protein,and increased the expression of Cyclin D1 mRNA and protein.Conclusion: Aβ_25-35decreases survival rate of synchronized PC12 cells and induces the apoptosis in a dose-dependent manner.Aβ_25-35 induced synchronized PC12 cells attempts to reenter cell cycle,and is arrested on S phase showing apoptotic peak subsequently.This is likely related to decreasing the P53 expression and increasing the Cyclin D expression.更多还原